A question on wave nature of EM radiation

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SUMMARY

The discussion centers on the relationship between frequency, distance, speed, and time in the context of electromagnetic (EM) radiation. The speed of light (c), approximately 3.0 x 10^8 m/s, is constant in a vacuum and can be used to calculate the time (t) required for EM radiation to travel a distance (y) using the formula t = y/c. The relationship between frequency (f), wavelength (λ), and speed is defined by the equation c = λν. Understanding these concepts is crucial for grasping the behavior of light in different media and the implications of refractive index.

PREREQUISITES
  • Understanding of electromagnetic radiation principles
  • Familiarity with the speed of light (c) and its implications
  • Knowledge of the relationship between frequency (f), wavelength (λ), and speed (c)
  • Basic concepts of quantum mechanics related to photons
NEXT STEPS
  • Study the derivation and applications of the equation c = λν
  • Explore the effects of refractive index on the speed of light in different media
  • Learn about phase velocity and group velocity in wave mechanics
  • Investigate the quantum mechanical model of light and its implications for photon behavior
USEFUL FOR

Students of physics, optical engineers, and anyone interested in the principles of electromagnetic radiation and its applications in various media.

SpaceExplorer
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There is a EM radiation of frequency suppose x Hz.Let it has to travel a distance of y m.Now what's the time required for the radiation to travel the distance?The question seems to be very easy, but my confusion is in how can the frequency,distance,speed and time can be related? Can someone give the relation along with the answer?
 
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v == c
s = ct
f = c / wavelength

Wavelength and frequency have nothing to do with the distance the light travels or the time it takes to get there. The frequency describes the oscillation of the electromagnetic field over time. The "wavelength" of the light is not the physical size of the photon but the distance the photon travels in going through one complete EM cycle.

Imagine a little blob of light moving in a straight line quickly oscillating from red to black to blue to black to red and so forth as it moves. The red and the blue represent the oscillations of the EM field. The wavelength is the distance the blob travels while doing a complete red/blue cycle.
 
hi
electromagnetic radiation speed is c i.e speed of light which is 3.0 x 10 ^8 m/s in air
It does not change except if it is traveling in a different medium
So divide distance y by c , you get the time t
 
Last edited:
SpaceExplorer said:
There is a EM radiation of frequency suppose x Hz.Let it has to travel a distance of y m.Now what's the time required for the radiation to travel the distance?The question seems to be very easy, but my confusion is in how can the frequency,distance,speed and time can be related? Can someone give the relation along with the answer?

As others have written, there's a clean relationship between the frequency, wavelength and speed (c = \lambda\nu). Confusion usually comes in when trying to understand this in terms of quantum mechanics, specifically the photon picture and the idea of refeactive index.

For your question, since you did not give a medium, the answer can't be given. But the general answer is t= c/n *y. Again, sources of confusion exist here, in terms of phase vs. group velocity. But, since you are assuming monochromatic light, there shouldn't be any issues.
 

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